Campfire lighter flint.
An example of the element Cerium

Campfire lighter flint.
This is basically a huge, 1/2" diameter x 2.5" long lighter flint, mounted in a case that has a sharp steel blade positioned so you can scrape it against the flint, creating a shower of sparks. The "Spin" and "Rotate" videos are actually video showing what it looks like when you scrape the flint with a file, generating even more sparks.Source: eBayContributor:Theodore GrayAcquired:16 April, 2009Text Updated:16 April, 2009Price: $30Size: 3"Purity: <20%